VGA Frame-Grabbers - Review and Selection Guide By Jeffrey Walt
Jun 06, 2008 in Hardware
Capturing a VGA signal, or even a DVI signal, in order to save it to a computer for archiving, editing, or even broadcasting requires a device called a framegrabber, or frame grabber. Whether you are looking for a VGA frame grabber or a DVI frame grabber, there are several choices that must be looked into before being able to make an informed decision about a purchase which this article will briefly discuss.
The first step is to determine what needs to be captured with the frame grabber. Framegrabbers are very versatile units and have the ability to capture from any VGA or DVI outputs. These devices are critical in many medical applications, such as creating digital archives of X-Ray imagery or ultrasound, military applications where frame grabbers are used to capture output from radar, and research applications where the output from scientific equipment is captured in real-time using a frame grabber. What’s more, all of these applications require an external solution due to size and security constraints. As long as a functioning VGA or DVI port is present, there is a frame grabber that will capture it. Thus, depending on what is being captured, the capture rate (frame rate) and resolution requirements need to be determined. The user also needs to determine if he/she is capturing a VGA signal or DVI signal.
Based on different characteristics, this article will analyze and compare digital and analog VGA and DVI frame grabbers from the following major manufacturers: Epiphan Systems, EMS Imaging, Foresight Imaging, Ncast, PixelSmart, and Unigraf.
Portability
Besides Epiphan Systems, all the manufacturers listed in the previous paragraph make PCI-based devices. What this means is that the frame grabber is bound to the computer in which it is enclosed. What’s more, a PCI frame grabber may not be used in conjunction with a laptop (notebook computer). Epiphan Systems takes a different approach to their frame grabbers, making them all external and using the common USB bus. This gives the user a significant advantage over PCI-based frame grabbers, as a USB-based device can be easily moved around between different devices and locations.
It would also be important to note that the USB to VGA frame grabbers from Epiphan are the only ones that are compatible with Windows, Linux, and Mac OS X.
Resolution
Knowing the highest resolution that will need to be captured is imperative in choosing the right image/video grabber. A frame grabber (more…)